There is a demand to find new cleaning and degreasing solvents to replace chlorinated hydrocarbons and chlorofluorocarbons. Cleaning and degreasing solvents are used to remove greases, oils, dirt and other undesired particles that accumulate on surfaces of metal articles during manufacture or repair of the articles. Typically the article is either sprayed with the solvent, submerged in a "dip tank" containing the solvent, or treated with hot vaporized solvent in a vapor degreasing chamber. After the solvent has been removed from the cleaned article, it can be shipped to the consumer or further processed in a subsequent operation. Chlorinated hydrocarbon and chlorofluorocarbon solvents have enjoyed wide use by metal fabricating industries especially the aerospace and electronic manufacturing industries as cleaning and degreasing solvents. These solvents have high solvating ability, are low boiling, and are relatively inexpensive to produce. However, in recent years use of these solvents has been restricted because of their toxicity and environmental hazards, particularly in light of the link between use of these solvents and destruction of the atmospheric ozone layer. Because alkyl bromides have not been found to be as detrimental to the environment, these solvents are rapidly replacing chlorinated hydrocarbons and chlorofluorocarbons as the preferred solvents for cleaning and degreasing operations.
Alkyl bromide solvents were not traditionally exploited as cleaning solvents primarily because of their high cost relative to the chlorinated hydrocarbons and chlorofluorocarbons. Furthermore, alkyl bromides readily react with metals such as aluminum, magnesium, copper, zinc, iron, titanium, tin and alloys of these metals that are commonly used to manufacture industrial components. Metal induced decomposition generates metal bromides, bromide salts and hydrobromic acid as some of the bromine decomposition species. Generation of these decomposition species is harmful to the metal articles. The metal bromides and some of the bromide salts are formed from metal ions leached from the metal, and the hydrobromic acid severely corrodes metals, further exacerbating the problems associated with using alkyl bromides as cleaning and degreasing solvents. Furthermore, these decomposition species often adhere to the metal surface, defeating the cleaning process.